Janitrol's gas central air and heat

[mlh]

I have a Janitrol's gas central air and heat. The air works fine, but the heat isn't working right. If I have the theromstat turned on 70 it never makes it to it, if it is real cold outside. I have to reset it to get it to heat up the house. Anyone know what the problem can be?
Thanks,

[Hube]

Mlh; WELCOME to the forum.... There are several causes when a unit cannot obtain the required setting. Among other things,the thermostat could be out of calibration, either in the senser or the "anticipator" setting.This is known as an "under-ride" ,when the burner fails to achieve the thermostat's set point, and cuts out too early. Unless you have a tester and/or the proper setting number, you would be best to re-new the thermostat or call in a tech, to adjust the old one. BTW, what make and model is this therm, as we may be able to give you some added info , to the problem. Hube